A130123 → D+1

OEIS matches ?

• A139756: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS
• A001787: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS
• A097067: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

Triangle begins:
  0: 1;
  1: 2, 2;
  2: 0, 8,  4;
  3: 0, 0, 24,  8;
  4: 0, 0,  0, 64,  16;
  5: 0, 0,  0,  0, 160,  32;
  6: 0, 0,  0,  0,   0, 384,  64;
  7: 0, 0,  0,  0,   0,   0, 896,  128;
  8: 0, 0,  0,  0,   0,   0,   0, 2048,  256;
  9: 0, 0,  0,  0,   0,   0,   0,    0, 4608, 512;

The row polynomials satisfy (n-1+x)*P(n,x) = (2*n*x+2*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.

P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((2*n*x + 2*x^2)*P[n - 1, x])/(n - 1 + x)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((2*n*x + 2*x^2)*v[i - 1])/(n - 1 + x)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

Proved properties

• Real-rooted. Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
  Every polynomial of the sequence has only real roots, inside the stated interval.
  by the cited steps: e-caef435f2360eea3
• Coefficients of one sign. Every nonzero row, n >= 0: the coefficients of P_n have one sign
  All coefficients of each polynomial have the same sign (after x -> -x when alternating).
  derived from the cited steps by a stated theorem: e-caef435f2360eea3
• Hadamard kernel (Malo). Rows P_n, n >= 0, are Hadamard kernels (preserve real-rootedness)
  Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.
  derived from the cited steps by a stated theorem: e-caef435f2360eea3

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

• preserver_image derivative_polynomial, shift 0 e-caef435f2360eea3

  Laguerre’s theorem on differential operators [SP14] polytool ?

  • premise (sequence): Infinite lower triangular matrix with 2^k in the right diagonal and the rest zeros. Triangle, T(n,k), n zeros followed …
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    • parent_provers periodic_product e-7963c2f0e7b86ba8 root: theorem check

      Parent-row provers of polytool polytool ?

    • preserver_image mobius, shift 0 e-37a63c273567eea5

      Affine, reversal and Möbius substitutions (elementary) polytool ?

      • premise (sequence): Infinite lower triangular matrix with 2^k in the right diagonal and the rest zeros. Triangle, T(n,k), n zeros followed …
        uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
        • ↵ parent_provers periodic_product e-7963c2f0e7b86ba8 (expanded above)

Related sequences ?

Same fingerprint (10)

Equal up to content, sign, reversal and a small index shift.

• A023531 → D+1
• A023531 → D → D+1
• A023531 → (θ+1)² → D+1
• basis-map coefficients of A021012 → D+1
• basis-map coefficients of A030528, shifted → D+1
• basis-map coefficients of A026729 → D+1
• A010054 → reverse → D+1
• A010054 → reverse → D+1
• A136572 → D+1
• basis-map coefficients of A026729, shifted → D+1

References

1. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.